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<HEAD><TITLE>Confidence Based Edge Detector</TITLE></HEAD>

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<font size=5><b>Edge Detection and Image Segmentation (EDISON) System</b></font>

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<b> Table of Contents </b>
<ul>
<li> <a href="help.html"> Introduction </a></li>
<li> <a href="overview.html"> System Overview </a></li>
<li> Confidence Based Edge Detector </li>
<li> <a href="segm.html"> Mean Shift Based Image Segmenter </a></li>
<li> <a href="syng.html"> Synergistic Image Segmenter </a></li>
<li> <a href="ref.html"> References </a></li>
</ul>
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<h5> Confidence Based Edge Detector </h5>

<p align=center><img src="./figs/edge_fig1.jpg"></p>

<p align=left>
This program implements the edge detection algorithm described in <a href="ref.html">[2]</a>.</p>
<p><u>Usage instructions:</u></p>
<ul type="disc">
  <li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
     mso-list:l0 level1 lfo1;tab-stops:list .5in">From the <b>File </b>menu
    select <b>Load image</b> to select and load an image (known formats: PNG,
    BMP,&nbsp;GIF, TIFF, JPEG, PNM, PGM, PPM).</li>
  <li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
     mso-list:l0 level1 lfo1;tab-stops:list .5in">To apply the edge detection
    algorithm on the image, from the <b>Edge Detect </b>menu select <b>Edge
    Detect</b> or simply press the <b>Edge Detect</b> button located in the
    upper left hand corner of the current edge detection frame. The detected
    edges are shown superimposed over the original image. The original image and
    detected edges are displayed when the <b>View Image </b>and <b>View Edges</b>
    checkboxes, located on the left of the current edge detection frame, are
    marked.<o:p>
    </o:p>
  </li>
  <li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
     mso-list:l0 level1 lfo1;tab-stops:list .5in">To save the edge map generated
    by the edge detection algorithm as a PGM file, from the <b>File</b> menu
    select <b>Save Edge Map</b>.</li>
</ul>
<p>The gradient rank-confidence space before non-maxima suppression is displayed
in the lower right panel of the current edge frame. The curve used for non-maxima
suppression is displayed within this frame. The same space after non-maxima
suppression is displayed in the upper right panel of the current edge detection
frame.<span style="mso-spacerun: yes">&nbsp; </span>The curves for hysteresis
thresholding (blue - high curve, red - low curve) are displayed within this
frame. <o:p>
</o:p>
</p>
<p>The shape and location of each curve may be modified. To change the location
of a curve select it and drag it with the mouse to the new location.<span style="mso-spacerun: yes">&nbsp;
</span>To change the shape of a curve right click the desired curve and select
the desired shape from the drop down menu. <o:p>
</o:p>
</p>
<p>One option displayed in this menu allows for the definition of a custom
shape. To create a custom shape, first add or delete nodes from the curve by
right clicking the mouse over the desired node location on the curve and
selecting either <b>Add Node</b> or <b>Delete Node</b> from the drop down menu.
Then drag these nodes to their respective locations to form the desired custom
curve. <o:p>
</o:p>
</p>
<p>The parameters generated by the above curves may also be entered manually. To
do so, from the <b>Edge Detect</b> menu select <b>Change Parameters</b> or click
on the <b>Parameters</b> button located on the left of the current edge detection
frame. This option also allows for changing the filter size and the minimum
number of pixels on an edge.<o:p>
</o:p>
</p>
<p class="MsoNormal"><u>NOTE</u>: After changing the parameters the edge map is
not automatically updated, you must <b>run the algorithm again</b> to see the
result.</p>

<p><a href="edge.html">top</a>

<hr>
<font color="#888888">Robust Image Understanding Lab, (freeware) 2002</font>

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